What is that big signal on AM with the marker that says K3FEF Part15? February 22, 2018 Michael-K3FEF 0 “K3FEF Part 15” Marker is an SSTran AMT3000 low power transmitter I use to demo my vintage AM radio collection. You never know what you’ll hear. 🙂 It is currently set to 1630AM and doesn’t reach beyond my property limits. Previous: How can I get in touch with you? Next: I don’t see anything in the waterfall, or it’s TOO bright! About The Author Michael-K3FEF Comment on this FAQ Cancel replyYou must be logged in to post a comment.